title: Quantum dots induce heat shock-related cytotoxicity at intracellular environment.
abstract: Quantum dots (QDs) are semiconductor nanocrystals with unique optical properties. Different proteins or polymers are commonly bound to their surfaces to improve biocompatibility. However, such surface modifications may not provide sufficient protection from cytotoxicity due to photodegradation and oxidative degradation. In this study, the cytotoxic effects of QDs, CdTe, and CdSe/ZnS were investigated using cadmium-resistant cells. CdTe QDs significantly reduced cell viability, whereas, CdSe/ZnS treatment did not markedly decrease the cell number. CdTe QDs were cytotoxic in cadmium-resistant cells suggesting that internalized QDs degraded and cadmium ions contributed to the cytotoxic effects. CdTe QDs were consistently more cytotoxic than CdSe/ZnS QDs, but both QDs as well as cadmium ions activated heat shock protein 70B' promoter. QDs themselves are likely to contribute to HSP70B' promoter activation in cadmium-resistant cells, because CdSe/ZnS QDs do not release sufficient cadmium to activate this promoter.
authors.affiliation: Biomaterials Unit, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki, 305-0044, Japan, migita@yz.yamagata-u.ac.jp.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Migita
authors.forename: Alexandre
authors.initials: A
authors.lastname: Moquin
authors.forename: Hitomi
authors.initials: H
authors.lastname: Fujishiro
authors.forename: Seiichiro
authors.initials: S
authors.lastname: Himeno
authors.forename: Dusica
authors.initials: D
authors.lastname: Maysinger
authors.forename: Françoise M
authors.initials: FM
authors.lastname: Winnik
authors.forename: Akiyoshi
authors.initials: A
authors.lastname: Taniguchi
mesh_terms: D000818:Animals; D002104:Cadmium / Q000009:adverse effects / Q000494:pharmacology; D019187:Cadmium Compounds / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology; D002470:Cell Survival / Q000187:drug effects; D018840:HSP70 Heat-Shock Proteins / Q000096:biosynthesis* / Q000235:genetics; D018869:Heat-Shock Response / Q000187:drug effects; D006358:Hot Temperature; D051379:Mice; D053758:Nanoparticles / Q000737:chemistry; D011401:Promoter Regions, Genetic / Q000187:drug effects; D045663:Quantum Dots / Q000009:adverse effects / Q000737:chemistry*; D018036:Selenium Compounds / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology; D013499:Surface Properties / Q000187:drug effects; D013691:Tellurium / Q000737:chemistry* / Q000494:pharmacology
chemical_list: D019187:Cadmium Compounds; D018840:HSP70 Heat-Shock Proteins; D018036:Selenium Compounds; D002104:Cadmium; C058667:cadmium selenide; D013691:Tellurium; C028337:cadmium telluride